Rationale behind doctrine of immutability of judgment

A judgment that lapses into finality becomes immutable and unalterable. It can neither be modified nor disturbed by courts in any manner even if the purpose of the modification is to correct perceived errors of fact or law. Parties cannot circumvent this principle by assailing the execution of the judgment. What cannot be done directly cannot be done indirectly.[1]

A final and executory judgment produces certain effects. Winning litigants are entitled to the satisfaction of the judgment through a writ of execution. On the other hand, courts are barred from modifying the rights and obligations of the parties, which had been adjudicated upon. They have the ministerial duty to issue a writ of execution to enforce the judgment. [2]

The rationale behind the rule was further explained in Social Security System v. Isip,[3] thus:

The doctrine of immutability and inalterability of a final judgment has a two-fold purpose: (1) to avoid delay in the administration of justice and thus, procedurally, to make orderly the discharge of judicial business and (2) to put an end to judicial controversies, at the risk of occasional errors, which is precisely why courts exist. Controversies cannot drag on indefinitely. The rights and obligations of every litigant must not hang in suspense for an indefinite period of time.[4]

[1] MERCURY DRUG V. HUANG (G.R. NO. 197654. AUGUST 30, 2017).

[2] Id.

[3] 549 Phil. 112 (2007) [Per J. Corona, En Banc].

[4] Id. at 116.